I just listened to a variety of recordings of the passage, and with the exception of Wilhelm Kempff, all of them seemed to hold the long r.h. notes in the second and fourth measures by their full value. The shorter notes seemed to vary more, but, in my estimation, only due to variations in tempo, and the more recent recordings seemed to stress the full duration a bit more than the older ones.

Thanks, Knut.The breaks are often minute in Classic style music and the actual length up to the taste and imagination of the player. They are also easily covered over with the pedal.

I just listened to recordings by Artur Schnabel, Friedrich Gulda, and Richard Goode and all used good stylistic articulation. I also heard some bad ones on Youtube that ran everything together with the fingers and the pedal as if playing a Romantic piece. In this music, the pedal should stay out of the way of the melody, and only enhance the holding through of the notes by the fingers in the accompaniment

Here is a blow by blow concerning the Beethoven example.

1. It would be bad style to connect the last note of m. 1 to the first of m. 2 as I heard several pianists do. It removes all distinction from the melody and turns it into a childish mush. The C in m. 2 is an important goal note matching the G in m. 4 and must stand out on its own.

2. The holding of the C in m.2 is up to the player's sense of phrasing. There is a danger of losing continuity at this point, so the break must be infinitesimal. No break at all would be unnatural, since it is the natural place for a breath.

3. Covering over the staccato breaks completely in m. 3 with the pedal as I heard one pianist do would be a no-no because it removes the vigorous and aggressive character of the music at this point. (Note the reinforcement in the left hand which might cause a player to play the left hand with the same staccato touch as the right hand and entirely without pedal.)

4. A greater sense of closure should occur after the G in m. 4 than the C in m. 2. How this is accomplished is up to the player. Some might make more of a break, some less, and the hand might break while the pedal sustains. What is most important is that there is a sense of completion with a new section starting on the last quarter note.

5. The two note slurred groups add a jaunty flavor that is brought out by clear articulation. But the last note of each group should not be so short as I heard several pianists play it, because it is an important connective tone leading on to an important goal, the Ab.

6. The break after the D in m. 5 was too short in the Kempf. The very expressive drop of a tritone needs projection and a longish last note. However, a minute break must occur after the D to show the beginning of the next leg of the melodic sequence. Yet, this break must not destroy the melodic unity of the D leading on to the Eb and F.

This theme is particularly hard to play, and I have never hear a completely satisfactory performance in a recording. But, believe it or not, Mozart's music has even greater requirements of the type described above than Beethoven. That could explain why there are not as many fine players of Mozart as there are of, say, Chopin.

When I was a young piano student, decades ago, I really wondered what was the point of a tenuto dash. If all notes were to be played to their full length by default anyway, what does one need a tenuto mark for? No one could give me a really satisfactory answer back then.

I don't know how that can be interpreted on the piano, but as a string player, I understand the tenuto symbols as "sustained dynamics throughout the note", and that has definitely nothing to do with the (rhythmical) length of the note, but the force or strength of the tone.

The tenuto notes should absolutely not oscillate in their force, even if a given phrase is ppp or fff.

Since that is entirely impossible to do on the keyboard, I believe it is rather a psychological intention. (I have seen a pianist playing vibrato on the keys..)

That's a great point, OCTO. So the tenuto marking means the same for the violin as on the piano: maintain the intensity of the note as is natural for your instrument. On the violin, the actual tone itself may be maintained, on the piano only the length. It is a cliche that if orchestral music is like a painting, piano music is like a drawing. The pianist creates the illusion of color with the means at hand.

To answer my own original question: I've discussed this elsewhere and come up with the following.

In the late 19th century (in UK choral singing, at least), it was apparently common practice for lengthy notes at the ends of phrases not to be held full-length, but rather just finished at the performer's leisure.
In order to combat this, C.V. Stanford taught his pupils (Vaughan-Williams, Howells, Holst, Ireland, Wood, Bliss, Bridge, Butterworth, etc) the 'trick' of adding a final quaver, so that singers would not come off the note early. This technique caught on throughout that generation of composers.

In modern performance, it is recommended that such notes are finished at the front of the quaver, not after it.

Just for the record, here's a source: Henry Mancini recommended this practice in his book "Sounds and Scores" from 1973 where he describes his arranging and orchestration techniques for Hollywood orchestras in the 60s/70s:

Just for the record, here's a source: Henry Mancini recommended this practice in his book "Sounds and Scores" from 1973 where he describes his arranging and orchestration techniques for Hollywood orchestras in the 60s/70s:

I was singing a piece of Carter recently, in which he used this tied quaver method. However, at one point, some voices had a crotchet tied to a quaver at the end of a phrase, followed by rests. But other parts had a crotchet followed by a different pitch on the quaver. So do we all sing the same length, or not? (It was harmonically viable to do either.)

I will continue to ask the conductor "Do you want us to knock off the quaver?", and then scribble over the quaver with a pencil if the answer is 'yes', which is what everyone has always done.

Just for the record, here's a source: Henry Mancini recommended this practice in his book "Sounds and Scores" from 1973 where he describes his arranging and orchestration techniques for Hollywood orchestras in the 60s/70s:

Mancini is somehow contradictory.
"If you want to end on the downbeat, write:" - well, write a rest on the downbeat, not a note.
What about ͜| - I think that would perfectly suit, but both are completely wrong.
Write tenuto and than the rest, IMO.

Lazy musicians, they got paid to play the whole note, so ink to print errata costs less.

Or schizophrenic composers. I have recently read (today actually) a part of a great and wonderful book by psychologist Rollo May "The Courage to Create" - at one point he described some patients in the mental hospitals always sitting or standing close to the walls, since there is no barrier in their mind, so they need to create a physical barrier in order to feel safe. When they have been given a blank paper to write their names, they wrote it on the edge of the paper..
Likewise, some schizophrenic composers need always to feel the barrier, just a simple note is "hanging" nowhere, like in a free fall - it needs a mental support.
BTW I am one of the above mentioned schizophrenic composers too.... I am trying to cure myself, but I think it is a global sickness.

*p.s. I warmly recommend Rollo May's book for all composers and creative persons! ISBN-13: 978-0393311068

Mancini's approach to such held notes is the complete opposite of that used by Bach, Mozart, Beethoven et. al. who avoided tied notes whenever possible. Personally, I prefer the music of the latter to the Pink Panther.

Thanks for the recommendation, OCTO. That books sounds very interesting.

Perhaps the lines in the previous post would look better, or cleaner, without hooks. And possibly less piano-centered. I might actually have seen something similar to this before, but, if so, it has completely slipped my mind where.